After periods of user inactivity, computers enter suspended states in which they are powered down (placed in “sleep mode”) in reduced power configurations. In a computer implementing a hypervisor which controls one or more guest operating systems to establish respective virtual machines using a single hardware processor, however, the hypervisor may isolate a guest operating system in such a way as to complicate entry into the sleep mode. Part of this complication arises from a diskless environment in which Internet Small Computer System Interface (iSCSI) is not as fast as a real disk or as fast as the guest O.S. expects it to be, and the hypervisor needs to finish key processes before the hardware enters the sleep mode.